The Missouri State Highway Patrol will take over security in Ferguson after local police were criticized for militarized tactics during four days of protests over the fatal police shooting of an unarmed black teenager, the governor said on Thursday.

Governor Jay Nixon named Highway Patrol Captain Ron Johnson, an African-American who grew up in the Ferguson area, to oversee the security effort.

"What's gone on here over the last few days is not what Missouri is about, it is not what Ferguson is about. This is a place where people work, go to school, raise their families and go to church, a diverse community, a Missouri community," Nixon said at a news conference in Ferguson, where he met with police, prosecutors and members of the community.

"But lately it has looked a little bit more like a war zone, and that is unacceptable."

Earlier U.S. President Barack Obama called on police to respect demonstrators in an attempt to defuse tensions in Ferguson after 18-year-old Michael Brown's death on Saturday set off demonstrations.

Lawmakers, activists and demonstrators have complained that the mostly white police force has escalated the violence by using military gear and tear gas. Police have said they will do better but have also justified tactics, saying they have responded to the threat of violence during protests.

Nixon said local police would not be pulled out of Ferguson but that state troopers would direct the team.

Additionally, U.S. Attorney General Eric Holder said in a statement that local police had accepted an offer of technical assistance "to help conduct crowd control and maintain public safety without relying on unnecessarily extreme displays of force."

In a brief statement Johnson promised respect for every citizen. There have been dozens of arrests over the last few days and complaints that police have come down too hard on protesters and on reporters covering the demonstrations.